The motivation is to make a smaller change to their operations and infrastructure. Right now they are running application services on linux machines using puppet to make the machine environment work. Switching to a container gives them reproducible environments that work on a developer workstation and a server. It also gives some operational benefits for how you run a process I think. You can do this without buying into the docker daemon, network overlay, orchestration. If you are currently able to deploy services on linux to production then you can do that, but with containers. This is an incremental win.